An experimental study on targeted therapy of radioiodinated cyclic cRGD peptide on melanoma bearing mice

Objective Ectogenic Arg-Gly-Asp(RGD)peptide can bind to integrin α2 β3 receptor on the cell membrane of tumor cells and neovasculature endothelial cells to prevent tumor growth and metas-tasis but was less potent than cRGD.The aim of this study wag to further understand the inhibitory effect of cRGD labeled with 131I in melanoma bearing mice.Methods cRGD peptide was labeled with 131I by Ch-T method under the optimum labeling conditions.Twenty mice were randomly (complete randomization) di-vided into four groups.five for each group.There were experimental group(131I-cRGD),cRGD control group.131l-Gly-Gly-Gly(cGGG)control group and phosphate buffered saline(PBS)control group.All mice were injected through tail vein.Tumor volume, weight and net weight (net weight =weight-the weight of the tumor)were measured for all and compared by one-way ANOVA.Results The labeling effi-ciency and the radiochemical purity of 131I-cRGD peptide were(89.14±4.57)%and(99.14±O.72)%respectively.Compared with the PBS group at 21st day, the tumor inhibitory rates were 64.92%for 131I-cRGD group.37.70% for cRGD group,and 24.78%for 131I-cGGG group respectively.When sacrificed at 28th day,the weight was(6.48±5.19)g for 131I-cRGD group,(10.81±6.25)g for cRGD group, (14.21±5.91)g for 131I-cGGG group,and(18.88±7.59)g for PBS group(F=3.479,P 0.05).Conclusion 131I-cRGD could effectively inhibit tumor growth in melanoma bearing mice and might be of potential in treating melano-ma in, the future. Key words: Melanoma; Tumor cells, cultured; Peptides,cyclic; Iodine radioisotopes; Mice